Best posts made by shadowphile

Latest posts made by shadowphile

From a different thread that looks very similar I need to use the M305 command and virtual heaters but I just couldnt understand the replies.
Im in the middle if a massive upgrade to my printer and so far my design has lightened my moving parts by 50 percent AND added a second extruder! New extruders are watercooled and fans replaced by directed air nozzles connected to air pump.
I built a waterblock cooler for my main extruder and need to shut down the heater using a thermistor if the waterblock (or water itself) rises above expected threshold (say 35 deg). I have a PT100 on the main extruder.
How exactly do I set this up? My chamber is not heated but Id like to keep that option open for the future. The second extruder will also have a PT100. My bed is heated also.
Another consideration: With a second extruder im just going to run the output of one waterjacket to the input of the second one so a fault would presumably shut down both heaters. (can't imagine it wouldnt but justing being safe)
thanks

thanks for the replies, it sounds like there isn't really an issue on the hardware side.
I've been learning Fusion360 and no issues there, just export the .nc file.
I'm also learning to use to Tormach CNC in our makerspace. These machines always come with their own software interfaces that do the same thing as the Duet webcontrol, but since that is printing-oriented, what would I use to manage the machine and jobs? Webcontrol can monitor progress, start and stop jobs, define tools and such, even jogging. But there are a lot of elements non relevant to cnc and cnc oriented items not in webcontrol (maybe setting the Duet to CNC mode also modifies the web interface to match?)

I've been using the Duet for my delta printer and now I'm shopping for a desktop milling machine (which ironically I need to make custom parts for the printer.)
I'm converging on the Shapeoko Nomad but it runs GRBL on an AT2560 Mega MPU, which now seems lame after using the Duet. GRBL only does 3 axes too and at some time I would like to design a fourth (rotary) axis or other extended capabilities.
So the Nomad would eventually be a hardware foundation for modding.
Would the Duet be good for this function? I know it has non-printing capabilities but not sure it would be a good true controller for the system.
Also, I'm only used to the Duet for printing, using the web interface. I can't imagine that interface is good for subtractive fabbing and any software that comes with the Nomad would be useless at this point. The Nomad is controlled by a PC streaming gcode so I'm not even sure what the interface would look like since the Duet runs it's own files.
Another thing that might be an issue is I'm not sure the Duet would be strong enough to drive motors pushing a milling head through material, which would be using external drivers. I did not see an obvious way to get the digital stepper motor signals off the Duet.
thanks

apologies if I already replied but I don't see my post here.
Anyway, thanks Dave, that makes total sense. I figured I might be oversimplifying the stepper loading.
Since you are here, can I get a nod from you about this:
-Since I don't want to change everything over to 24V, I plan to wire 24 into the Duet but wire my old 12 into the middle pin of the V_fan select header. Both supplies would merge their negative terminals. Sound ok?

@phaedrux I'm going to chose to understand the power supply body styles, it's not a huge deal and the sealed unit is still quite long. I'm used to the caged type in general.

I'm still confused about the power supply specs lets just skip the voltage part.
-Motors are 2 amps, derated to 1.7 each. Three motors makes that 5.1 amps drawn from the supply, regardless of the supply voltage.
To keep this simple lets just ignore the other loads and overhead.
Do I just choose a 24V module with at least 5.1 amps? (which is a 122W supply).
Or do I chose a supply based on the documentation, which is 2A^2*1.4ohm in my case? For three motors that is only about 18W.
Which is right? One of my assumptions is vastly wrong.

thanks Phaedrux. I already read the first but no mention of trade-off of current wrt 12 and 24 supplies. The others are new to me but still don't address my question. Maybe I don't understand the details enough but here my working calculations:
-my steppers are rated at 2 amp, so 85% of three of those is 5.1 amps.
-but the rated voltage on these is only 3.5V. That means 3.5*5.1 = 18.85 *1.5 for overhead = about 27 watts.

A 27 watt, 24V supply will only source about 1 amp, WAY below the 5.1 amps above. To get the required current means a way oversized power supply of 125W. Since the stepper drivers are not switching power supplies, you can't trade voltage for current to source high-current to the steppers and still use a low-power supply. This is my conundrum.

I have calculated that I need 100 watts for my system. I am upgrading from 12V to 24V but that also drops the rated output current, but my steppers will still draw the same amount (of current) as before. The total expected current of my three steppers is more than the rated output current of the 24V. I know of things like peak vs continuous, etc but I need a rule of thumb here.
BTW, if anybody here can recommend a 24 v supply in the power range that is SMALL, please give me a link. All the 100+ units I can find are like 8" long, except for the DIN-mounted expensive versions.
thanks

thanks for the overview Phaedrux, that helps keep calibration from turning into a exercise in OCD behavior
A few comments:
-There is some discussion about whether micrometers are better than calipers. I always get a lower value when using just the first few millimeters of the caliper tips.
-The wall thickness may change as the extrude moves from one corner to another (printing a cube) so the middle is probably the best one-spot measurement to make.
-I've found that one side often differs from the other three, probably because that side is right after the layer change (unless you have retractions turned off)
-I really liked some of the scripted test prints such as the pressure-advance-test-wall python script in this forum. Those would be good for your document. Changing over a range of parameter values during a print are impossible to do manually or with a slicer.
-How to differentiate the source of artifacts can be difficult. Thick corners can be from any or a combination of pressure-advance, accel/jerk/vel, and non-linear extrusion.